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3 door Cosworth misfire?

Old 28-03-2015, 11:13 PM
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dave99
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Default 3 door Cosworth misfire?

Hi All,
My friends Cossie 3 door failed the test on emissions. The CO reads 9.13% and HC 584 ppm!!
When the mixture is lowered at the ECU, the engine develops a misfire, causing the CO and HC to rise.
The injectors have been checked, my leads rotor and cap tried and plugs changed.
All ECU pins have been checked for faults.....


The primary ignition has been tested and is ok, secondary ignition shows a misfire
Has anyone here experienced this?


Are we barking up the wrong tree!!!


Thanks,


Dave

Last edited by dave99; 28-03-2015 at 11:40 PM.
Old 29-03-2015, 09:25 PM
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bump bump
Old 03-04-2015, 08:48 AM
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Guinnless
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Back to basics first.

Is the engine in good general condition?

i) cam timing correct
ii) compression ok
iii) all sensors in good condition and gapped correctly
iv) rotor arm correctly aligned with the groove on the distributor body
v) listen for air leaks, check all vacuum/boost hoses.

What plugs and gaps are you using?
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Old 03-04-2015, 09:28 PM
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Thanks Steve,
I have made some progress on this, I will keep you posted over the weekend.
Thanks again,
Dave
Old 13-04-2015, 09:12 PM
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dave99
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Sorry for the delay

I removed the fuel pressure regulator, piped to compressor and turned air regulator up until the fuel regulator started to blow off at 3.5 bar.
So all looked good....or so I thought!!
I placed the regular in a basin of water at 2.5 to 3 bar. The air from the compressor was escaping through the vacuum port.
Therefore, when the regulator is working on the fuel rail, some of the excess fuel is entering the engine via the vacuum hose!
Anyone out there selling a fuel pressure reg!!

Thanks for the help again,
Dave
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